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PubMed2000

Sampling methods for ventilator-associated pneumonia: validation using different histologic and microbiological references.

OBJECTIVE: To validate sampling techniques (tracheobronchial aspirates, protected specimen brush, and bronchoalveolar lavage, both conventional and protected) for the detection of ventilator-associated pneumonia (VAP) and causative microorganisms according to different histologic and microbiological references. DESIGN: Immediate, multiple bilateral lung biopsy, postmortem study. SETTING: Respiratory intensive care unit of a 1,000-bed teaching hospital. PATIENTS: Twenty-five mechanically ventilated patients (>72 hrs) who died in our intensive care unit. MEASUREMENTS: Lung tissue histologic examination and quantitative cultures (16 specimens/patient). The following four references for the diagnostic techniques were used: histology of guided lung biopsy, histology of blind lung biopsy, combined guided and blind lung biopsy histology and microbiology of lung tissue, and microbiology of lung tissue. RESULTS: Sensitivities when histologic reference tests were used ranged from 16% to almost 40%, whereas specificity rates were always <80%. When we combined both lung histology of guided or blind specimens and microbiology of lung tissue, all diagnostic techniques achieved considerably higher but still limited diagnostic yields (sensitivity range 43% to 83%; specificity range 67% to 91%). Causative organisms were missed in a significant number of cases by all techniques (17% to 83%). CONCLUSIONS: The diagnostic performances of different diagnostic techniques strongly depend on the reference used. All techniques for detecting VAP are of limited value. Finding a balance between clinical judgment and microbiological results is crucial to appropriately manage patients with VAP.

Biopsy↗

PubMed2000

Methods of measurement of image quality in teleultrasound.

In recent years, teleultrasound has emerged as a potentially effective method of provision of ultrasound services to remote areas of the community. Transmission of teleultrasound, however, requires a high degree of compression when utilizing the relatively low bandwidth ISDN connections available within the UK. The actual amount of compression occurring varies both with the connection and the image content, often on a frame to frame basis. For this reason, traditional measurements of image quality using test tools are ineffective. Most studies to date have assessed equipment performance by testing diagnostic performance. Although this is the most important method of assessing the results of image degradation, few studies have attempted to perform physical measurements of degradation. The aims of this study were to measure the amount of degradation within a teleultrasound system and, using a number of methods, to ascertain the most useful indicators of loss of image quality. Groups of successive abdominal ultrasound images were captured and digitized both before and after degradation via an ISDN6 teleultrasound system. Normalized mean squared error (NMSE), pixel histograms, line and surface plots, Fourier spectra and contrast measurements were carried out on regions of interest in both sets of images. The NMSE was most sensitive to degradation, with alterations in the NMSE value depending on image content and degree of degradation. Fourier analysis was also indicative, showing consistent changes in high frequency content again varying with image content.

Fourier Analysis↗

PubMed2001

Improved diagnostic classification of alcohol abusers by combining carbohydrate-deficient transferrin and gamma-glutamyltransferase.

BACKGROUND: Biochemical markers can provide objective evidence of high alcohol consumption. However, currently available markers have limitations in their diagnostic performance. METHODS: The diagnostic values of the most frequently used markers [carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), aspartate aminotransferase, alanine aminotransferase, and mean corpuscular volume] were studied in an analysis of six different clinical studies (n = 1412) on alcohol abusers and social drinkers. The purpose of the analyses was to determine whether a combination of markers would improve the diagnosis of subjects. RESULTS: Discrimination between alcohol abusers and social drinkers, as measured by the areas under nonparametric ROC plots, was significantly better (P<0.001) for the new combined marker [gamma-CDT = 0.8. ln(GGT) + 1.3. ln(CDT)] than for any of the separate markers or combination of CDT or GGT with other markers. The cutoff values for gamma-CDT (6.5) can be taken to be the same among males and females. CONCLUSIONS: The combined variable gamma-CDT is a powerful tool to discriminate alcohol abusers from social drinkers and is recommended for clinical use.

Alcohol Drinking↗

PubMed1993

The value of the forced expiratory time in the physical diagnosis of obstructive airways disease.

OBJECTIVE: To evaluate the test characteristics of the forced expiratory time (FET) in the diagnosis of obstructive airways disease. DESIGN: A cross-sectional diagnostic test study. The FET of 400 subjects was measured by a physician examiner and was compared with the criterion standard of spirometry. In a second sample of 100 subjects, the FET was measured by pairs of physician examiners to evaluate interexaminer agreement. SETTING: A pulmonary function test laboratory at a tertiary care hospital that receives referrals for preoperative evaluations, acute and chronic pulmonary disease, and occupational lung disease. SUBJECTS: A consecutive sample of patients who were referred to the pulmonary function laboratory from primary care internists, pulmonary physicians, and surgeons. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The sensitivity and specificity of the FET in the diagnosis of obstructive airways disease at cutoff values ranging from 2 to 14 seconds. A receiver operating characteristic curve was used to evaluate the diagnostic performance of the FET. Likelihood ratio lines were determined using a logistic regression model adjusting for the subjects age. Interexaminer agreement was evaluated with a kappa statistic. RESULTS: Using the FET maneuver with a cutoff value of 6 seconds will correctly diagnose the greatest number of subjects with obstructive airways disease. The FET maneuver is more discriminating for subjects 60 years or older compared with younger subjects. The positive likelihood ratio for a subject aged 60 years or older with an FET of 4 to 6 seconds is 0.42 (95% confidence interval [CI], 0.24 to 0.73); of 6 to 8 seconds, 2.19 (95% CI, 1.02 to 4.80); and of greater than 8 seconds, 4.08 (95% CI, 2.54 to 6.79). The kappa statistic for interexaminer agreement is 0.70. CONCLUSIONS: The FET demonstrates moderately good performance as a diagnostic test for obstructive airways disease. The value of the test will depend on the pretest probability of disease and the clinical circumstances in which it is used.

Adult↗

PubMed2006

Pulmonary nodules: estimation of malignancy at thin-section helical CT--effect of computer-aided diagnosis on performance of radiologists.

PURPOSE: To evaluate the effect of a computer-aided diagnosis (CAD) system on the diagnostic performance of radiologists for the estimation of the malignancy of pulmonary nodules on thin-section helical computed tomographic (CT) scans. MATERIALS AND METHODS: The institutional review board approved use of the CT database; informed specific study-related consent was waived. The institutional review board approved participation of radiologists; informed consent was obtained from all observers. Thirty-three (18 malignant, 15 benign) pulmonary nodules of less than 3.0 cm in maximal diameter were evaluated. Receiver operating characteristic (ROC) analysis with a continuous rating scale was used to compare observer performance for the estimation of the likelihood of malignancy first without and then with the CAD system. The participants were 10 board-certified radiologists and nine radiology residents. RESULTS: For all 19 participants, the mean area under the best-fit ROC curve (A(z)) values achieved without and with the CAD system were 0.843 +/- 0.097 (standard deviation) and 0.924 +/- 0.043, respectively. The difference was significant (P = .021). The mean A(z) values achieved without and with the CAD system were 0.910 +/- 0.052 and 0.944 +/- 0.040, respectively, for the 10 board-certified radiologists (P = .190) and 0.768 +/- 0.078 and 0.901 +/- 0.036, respectively, for the nine radiology residents (P = .009). CONCLUSION: Use of the CAD system significantly (P = .009) improved the diagnostic performance of radiology residents for assessment of the malignancy of pulmonary nodules; however, it did not improve that of board-certified radiologists.

Adenocarcinoma↗

PubMed2002

Detection of antibodies to deiminated recombinant rat filaggrin by enzyme-linked immunosorbent assay: a highly effective test for the diagnosis of rheumatoid arthritis.

OBJECTIVE: To assay antifilaggrin autoantibodies, we developed an enzyme-linked immunosorbent assay (ELISA) using a "citrullinated" recombinant rat filaggrin. Our objectives were to assess its value for diagnosing rheumatoid arthritis (RA) and to compare the results with those obtained using 4 other reference methods for detection of antifilaggrin autoantibodies, including the commercially available ELISA that uses a modified "citrullinated" synthetic peptide derived from the sequence of human filaggrin (CCP-ELISA). METHODS: We analyzed 711 sera from patients with well-characterized rheumatic diseases, including 240 patients with RA. Antifilaggrin autoantibodies were detected by an ELISA using a recombinant rat filaggrin deiminated in vitro as immunosorbent (ArFA-ELISA). The results considered were the differences between the optical densities obtained on deiminated and nondeiminated proteins. Antibodies to rat esophagus epithelium were detected by indirect immunofluorescence, while antibodies to human filaggrin were detected by immunoblotting and by a recently described ELISA using a deiminated recombinant human filaggrin. Finally, CCP-ELISA was performed according to the manufacturer's recommendations. RESULTS: At the titer thresholds allowing diagnostic specificities of 0.95, 0.985, and 0.99 to be reached, the diagnostic sensitivities of the ArFA-ELISA were 0.76, 0.67, and 0.65, respectively. At these 3 thresholds, the sensitivities were significantly higher than those of the 4 other tests. Despite incomplete overlapping of the 5 tests, the high diagnostic performance of the ArFA-ELISA allows us to propose this test to replace all the other methods for antifilaggrin autoantibody detection. CONCLUSION: ArFA-ELISA appears to be the most efficient test among those available for the detection of antifilaggrin autoantibodies, in terms of diagnostic accuracy for RA. Its diagnostic performance in early RA and its prognostic value are currently under evaluation.

Adolescent↗

PubMed2006

Variability in the performance of nuclear matrix protein 22 for the detection of bladder cancer.

PURPOSE: We assessed variability in the diagnostic performance of NMP22 for detecting recurrence and progression in patients with Ta, T1, and/or CIS transitional cell carcinoma of the bladder in a large international cohort. MATERIALS AND METHODS: NMP22 voided urine levels were measured in 2,871 patients who underwent office cystoscopy for monitoring previous stage Ta, T1 and/or CIS transitional cell carcinoma at 12 participating institutions. RESULTS: Patient characteristics varied considerably among institutions. Overall 1,045 patients (36.4%) had recurrent transitional cell carcinoma (range across institutions 13.6% to 54.3%). Median NMP22 was 5.5 U/ml (range across institutions 2.5 to 18.8). Of the patients 33.5% had grade III tumors (range across institutions 20.6% to 54.0%) and 22.4% had muscle invasive tumors (range across institutions 3.2% to 38.2%). Area under the ROC curve for bladder TCC detection was 0.735 (95% CI 0.715 to 0.755, range across institutions 0.676 to 0.889). The manufacturer recommended cutoff of 10 U/ml detected 57% of cases with a 19% false-positive rate. AUC for grade III and stage T2 or greater disease was 0.806 (95% CI 0.780 to 831) and 0.864 (95% CI 0.839 to 0.890), respectively. For each NMP22 cutoff NMP22 had higher sensitivity for detecting grade III and stage T2 or greater bladder transitional cell carcinoma than for detecting any cancer. No optimal cutoffs for detecting any or aggressive bladder transitional cell carcinoma could be derived based on NMP22 values. CONCLUSIONS: There is a substantial degree of heterogeneity in the diagnostic performance of NMP22 applied to populations from different institutions. There is no clearly defined NMP22 cutoff but there is a continuum of risk for recurrence and progression.

Adult↗

PubMed2002

Combining free and total prostate specific antigen assays from different manufacturers: the pitfalls.

OBJECTIVES: We investigated the impact of interchanging free prostate specific antigen (f-PSA) concentrations from 10 different assays over a reference total PSA (t-PSA) on predicting prostate histology with free-to-total PSA ratios (f/t-PSA). METHODS: Archival sera from 80 t-PSA- and age-matched pairs of histologically confirmed prostate cancer (PCA) and benign prostatic hyperplasia (BPH) patients with t-PSA levels between 2 and 25 microg/l were investigated. Serum aliquots were analyzed for t- and f-PSA using a reference method (Access, Beckmann-Coulter Hybritech) and 10 commercially available f-PSA assays. Passing Bablok and linear regression were performed to investigate the interassay agreement between f-PSA assays. To compare diagnostic performance, ROC curves for PCA detection were calculated for the 10 f/t-PSA combinations using the reference t-PSA as denominator. Sensitivities, specificities and f/t-PSA cut-offs were calculated for varying points of the ROC curve. RESULTS: Despite good correlation of all 10 f-PSA assays with the reference method 4 showed significantly lower mean f-PSA levels. For f/t-PSA as a predictor of prostate histology, areas under the ROC curve (AUC) varied between 0.65 and 0.71 and, if compared to the reference method (AUC=0.70), were significantly lower in three cases. Ensuring 80% specificity, sensitivities ranged between 34% and 54% (reference method: 53%) and f/t-PSA cutpoints differed considerably depending on the f-PSA assay used (range: 0.15-0.24; reference: 0.15). Similar variations were noted at 95% specificity and 80% and 95% sensitivity. CONCLUSIONS: Arbitrary combinations of f- and t-PSA assays should not be used to calculate f/t-PSA ratios unless adequate studies have validated the diagnostic performance and cut-offs of that particular assay choice.

Aged↗

PubMed2000

[Tuberculosis and human immunodeficiency virus infection: clinical manifestations and performance of diagnostic procedures according to distinct forms of the localization of disease].

OBJECTIVES: To analyse the clinical manifestations and performance of the diagnosis methods in tuberculosis (TB) diagnosed in patients with human immunodeficiency virus infection (HIV), according to the location forms of disease (LF). MATERIAL AND METHODS: We revised 80 cases of TB diagnosed in patients with infection by HIV. The data were gathered in relation to TB location, the clinical data and the microbiological and histological diagnosed studies. In the statistic analysis the values p < 0.05 were taken into account. RESULTS: The prevalence of LF was: 1) pulmonary forms (PF) 32 (40%), of which 12 were typical pulmonary (TP) and 20 atypical pulmonary (AP); 2) mixed forms (MF) 21 (26%); 3) extrapulmonary forms (EF) 19 (24%), of which 17 were lymphadenitis; 4) miliary tuberculosis (MT) 8 cases (10%). The prevailing symptoms were: fever (71%) mainly in MF and MT, cough (69%), with less frequency in AP, EF and MT (p < 0.05) and adenomegalies especially in EF and MF. The diagnosis was based on the study of the sputum smears and lymph node. The bacilloscope of the spontaneous sputum was 53% with a minor performance in the AP (p < 0.05), while in lymph node the smear for AFB was positive in 78% cases and caseous granulomas were observed in 87%. CONCLUSIONS: In our study the major confirmed locations were pulmonary and lymph node, the most important clinical symptoms were fever, cough and adenomegalies. The diagnosis was based, in the most of cases, on the microbiologic and histologic examination of bronchial secretion and lymph node samples.

AIDS-Related Opportunistic Infections↗

PubMed2001

Detection of Chlamydia trachomatis in genitourinary medicine clinic attendees: comparison of strand displacement amplification and the ligase chain reaction.

Nucleic acid amplification (NAA) methods for the diagnosis of genital Chlamydia trachomatis infection perform well but are technically demanding. Strand displacement amplification (SDA) assay is a new NAA method that offers technical simplicity but its comparative diagnostic performance is unknown. Here, we compare the diagnostic performance of ligase chain reaction with that of SDA in first-catch urine (FCU) samples from both male and female patients and in endocervical swab (ECS) specimens. Attendees (715 men, 291 women) of a city-centre genitourinary medicine clinic were studied. FCU specimens were collected from all the men and from 205 of the women in the study. Two ECS specimens were collected from each of the women. Discordant results were resolved using an in-house nested polymerase chain reaction technique. Samples positive in two out of the three assays were considered positive. Prevalence of C. trachomatis infection was 9.2% and 9.1% in the men and women, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of SDA in FCU specimens from the men were 95.5%, 100%, 100% and 99.5%, respectively. In the female group, the figures for FCU and ECS specimens were 77.3%, 100%, 100% and 97.3%, and 90.9%, 100%, 100% and 97.3%, respectively. In this high-prevalence population, SDA assay is an effective method for the detection of C. trachomatis in FCU specimens in men and in ECS (but not FCU) specimens in women. Further studies in lower-prevalence populations are required.

Chlamydia Infections↗

PubMed2000

Selective use of diagnostic laparoscopy in patients with suspected appendicitis.

BACKGROUND: Diagnostic laparoscopy has been introduced as a new diagnostic tool for patients with acute appendicitis. We performed diagnostic laparoscopy when the clinical diagnosis of appendicitis was in doubt. The aims of this study were to evaluate this strategy and to analyze the efficacy of diagnostic laparoscopy in patients with suspected appendicitis. PATIENTS AND METHODS: All patients referred to our hospital with suspected appendicitis during the period 1994-1997 were evaluated prospectively. The clinical diagnosis was determined by the surgeon or resident on call based on the patient's history, physical examination, and leukocyte count. The patients were divided into three groups: group 1: appendicitis not likely. These patients were observed for 24 h or discharged. When they showed signs of appendicitis in 24 h, they were transferred to either group 2 or 3; group 2: doubt concerning diagnosis. These patients underwent diagnostic laparoscopy, and appendectomy was performed if indicated; group 3: In these patients the diagnosis appendicitis was felt to be certain. They were treated by primary appendectomy by an open procedure. In this study, 1,050 patients, 531 women (51%), 389 men (37%), and 130 children (12%) <11 yrs, were evaluated. RESULTS: Altogether, 377 diagnostic laparoscopies were performed, leaving 109 healthy-looking appendices in place. This reduced the negative appendectomy rate from 25% to 14% in all surgically managed patients. The negative appendectomy rate for the women in group 2 was reduced from 49% to 14%, and for the men from 22% to 11%, so it also seemed worthwhile to perform diagnostic laparoscopy in men. Because the appendix sana was left in place in only three children, the benefit from laparoscopy is relatively small for children. In 48% of these patients a second diagnosis was obtained, most of them gynecologic in nature. There were no false-negative laparoscopies and no complications resulting from the laparoscopic procedure. CONCLUSIONS: Diagnostic laparoscopy is a safe procedure that reduced the appendix sana rate without increasing the total number of operations. It is a useful method for obtaining other, mostly gynecologic, diagnoses. To further reduce the appendix sana rate, better criteria for laparoscopic assessment of the appendix are needed.

Acute Disease↗

PubMed2001

Remote sonographic interpretation using a laser printer network: system performance and diagnostic accuracy in actual clinical practice.

OBJECTIVE: The purpose of our study was to evaluate the technical and clinical performance of remote sonographic interpretation using a laser printer network connecting a community-based imaging center and an academic medical center. SUBJECTS AND METHODS: During a 3-month period, 161 consecutive sonographic examinations were performed at a community-based imaging center and all 161 patients were enrolled in the study. Seventy-one (44%) of 161 examinations were interpreted on-site at the community-based imaging center, and 90 (56%) of 161 were transmitted over a T-1 line to an academic medical center where the static images were interpreted remotely. For the purposes of this study, the examination time was defined as the interval from the time the technologist started to scan the patient to the time the patient was dismissed from the radiology department. Examination times were recorded for each patient. Follow-up was available for 92 (57%) of 161 studies. Sensitivity and specificity for studies interpreted at the community-based imaging center and at the academic medical center were calculated. RESULTS: The mean examination time for pelvic sonographic examinations interpreted at the academic medical center (43 min) was significantly longer than for scans interpreted at the community-based imaging center (31 min) (p < 0.01). However, no significant difference was noted in the examination time for abdominal sonography. For all examinations interpreted on-site at the community-based imaging center for which follow-up was available, the sensitivity and specificity were 95% and 100%, respectively. For all examinations interpreted remotely at the academic medical center for which follow-up was available, the sensitivity and specificity were 93% and 90%, respectively. No significant difference was seen in the sensitivity (p = 1.00) or specificity (p = 0.24) of studies interpreted on-site versus remotely. CONCLUSION: Static sonographic images can be interpreted remotely without loss of sensitivity, but with decreased specificity. However, more time must be allotted for performing pelvic sonography when these examinations are to be interpreted remotely.

Abdomen↗

PubMedDate not supplied

Evaluation of competing diagnostic tests: sequences for the diagnosis of pulmonary embolism, Part II.

Tests for pulmonary embolism (PE) and its most frequent source, deep vein thrombosis, include angiography, ventilation-perfusion nuclear medicine scans, and contrast and radionuclide venography. Although selective angiography is the definitive procedure for diagnosis of PE, its risk of death, although small, as well as the morbidity associated with contrast injections, is high enough that alternative, less accurate but safer, diagnostic procedures are preferred. Part I of this report described the methodology for selection of the single test having the lowest effective cost based on the test cost, its risks, and diagnostic performance. Other than the pulmonary angiogram, however, no single test has a sufficiently high diagnostic performance to be clinically realistic: incorrect diagnoses can result in sudden death. Sequences of tests or algorithms can be used to lower the overall risk of the tests to patients while increasing correct decision making to reach a clinically acceptable level. These points are illustrated by comparing three commonly recommended algorithms for the diagnosis of PE. Additionally, the prevalence of PE affects the choice of the algorithm, and we found that no single algorithm is best for all values of prevalence. In summary, we found that the most cost-effective strategy was to select the particular algorithm having the lowest effective cost for the relevant prevalence value. Use of algorithms also decreased the overall risk of diagnostic test complications and the number of incorrect diagnoses.

Algorithms↗

PubMed2002

Pre-operative diagnosis of pigmented skin lesions: in vivo dermoscopy performs better than dermoscopy on photographic images.

BACKGROUND: Epiluminescence microscopy (ELM) (dermoscopy, dermatoscopy) is a technique for non-invasive diagnosis of pigmented skin lesions that improves the diagnostic performance of dermatologists. Little is known about the possible influence of associated clinical features on the reliability of dermoscopic diagnosis during in vivo examination. OBJECTIVE: To compare diagnostic performance of in vivo dermoscopy (combined clinical and dermoscopic examination) with that of dermoscopy performed on photographic slides (pure dermoscopy). DESIGN: This case series comprised 256 pigmented skin lesions consecutively identified as suspicious or equivocal during examination in a general dermatological clinic. Clinical examination and in vivo dermoscopy were performed before excision by two trained dermatologists. The same observers carried out dermoscopy on photographic slides at a later time, and these three diagnostic classifications were reviewed together with the histological findings for the individual lesions. This was carried out in a university hospital. RESULTS: In vivo dermoscopy performed better than dermoscopy on photographic slides for classification of pigmented skin lesions compared with histological diagnosis, and both performed better than general clinical diagnosis. In vivo dermoscopic diagnosis of melanoma showed 98.1% sensitivity, 95.5% specificity and 96.1% diagnostic accuracy while dermoscopic diagnosis of melanoma on photographic slides was less reliable with 81.5% sensitivity, 86.7% specificity and 85.2% diagnostic accuracy. In particular, diagnosis of melanoma based on photographic slides led to nine false negative cases (three in situ, six invasive; thickness ranges 0.2-1.5 mm). CONCLUSIONS: In vivo dermoscopy, i.e. combined clinical and dermoscopic examination, is more reliable than dermoscopy on photographic slides. In clinical practice, therefore, in vivo dermoscopy cannot be considered independent from associated clinical characteristics of the lesions, which help the trained observer to reach a more precise classification. This may have implications on the reliability of ELM diagnosis made by an observer not fully trained in the clinical diagnosis of pigmented skin lesions or by a remote observer during digital ELM teleconsultation.

Adult↗

PubMed2005

Coronary artery disease: myocardial perfusion MR imaging with sensitivity encoding versus conventional angiography.

PURPOSE: To evaluate the technical performance of sensitivity encoding (SENSE)-accelerated myocardial perfusion magnetic resonance (MR) imaging and prospectively assess the diagnostic accuracy of this examination for depiction of significant coronary artery disease (CAD). MATERIALS AND METHODS: All 102 subjects provided written informed consent, and the local ethics committee approved the study. A saturation-recovery segmented k-space gradient-echo pulse sequence was combined with SENSE to allow dynamic acquisition of myocardial perfusion data on four parallel short-axis MR image sections at every heartbeat. This technique was evaluated in 10 healthy volunteers and in 92 patients scheduled to undergo conventional coronary angiography. Gadopentetate dimeglumine was peripherally injected at rest and during adenosine-induced stress. The maximal upslope of the signal intensity-time profiles was plotted for 16 myocardial segments defined on three MR image sections, and a myocardial perfusion reserve index (MPRI) between stress and rest, normalized to the input function from the blood pool of the most basal section, was calculated. Areas under receiver operating characteristic curves (AUCs) were used to assess the diagnostic performance of cardiac MR imaging for depiction of greater than 70% CAD seen at coronary angiography, the reference standard. RESULTS: In volunteers, the mean myocardial enhancement was 2.1 +/- 1.2 (standard deviation), with homogeneous signal intensity distribution across the segments. The diagnostic accuracy of MPRI measurements was high (AUC, 0.908; sensitivity, 88% [52 of 59 patients]; specificity, 82% [27 of 33 patients]). Diagnostic performance was similar among separate analyses of the three coronary territories and among separate analyses of data in the patients with diabetes mellitus, left ventricular hypertrophy, or myocardial infarction. CONCLUSION: Multisection myocardial perfusion MR imaging with SENSE is feasible and has high diagnostic accuracy in the detection of CAD.

Adult↗

PubMed1989

Early diagnosis of acute myocardial infarction. A comparison between chemical predictors.

Consecutive patients (n = 155) admitted to coronary care units at three different hospitals were investigated. The overall prevalence of acute myocardial infarction (AMI) was 0.45. The predictive potential with respect to AMI was tested for S-myoglobin, total S-creatine kinase (Tot-CK), and its MB isoenzyme as well as combinations of the different components. S-Myoglobin was determined by latex agglutination (MYO1) and radio-immunoassay (MYO2). The isoenzymes were determined as mass (CKMB1) and catalytic (CKMB2) concentrations. Biochemical tests were performed at arrival and at about 3h, 6h and 12h after the onset of symptoms (chest pain). Diagnostic performance of MYO1 was similar to MYO2 and CKMB2 similar to that of CKMB1. Single components did not show acceptable performance. In the period 6-12 h, combinations of total CK with CK-MB or myoglobin performed equally, with sensitivities of 0.96-0.98 and predictive values of a negative test (PV-) of 0.96-0.98. In view of increasing diagnostic performance for total CK and CKMB following 12 h after the onset of symptoms contrary to a decreasing performance for myoglobin combinations, total CK and CKMB should be used for the early diagnosis of AMI.

Adult↗

PubMed1988

The role of precision in determining the performance of a thyrotropin assay in diagnosing hyperthyroidism.

We examined the relationship between analytical sensitivity, precision at the lower limit of the reference interval, and diagnostic performance in hyperthyroidism for one radioimmunoassay and five immunometric assay kits for thyrotropin. The analytical sensitivity of these kits extended from 0.05 to 1.56 milli-int. units/L. Diagnostic efficiencies of the immunometric assays, in discriminating between euthyroidism and hyperthyroidism, ranged between 93% and 98%. There was a highly significant correlation (r = 0.99, P less than 0.001) between analytical sensitivity and diagnostic efficiency. The between-assay coefficients of variations, at the lower limit of the reference interval, ranged from 26% to 87%. There was no correlation (r = 0.36) between precision, at this concentration, and diagnostic efficiency. We conclude that analytical sensitivity and not precision is the major determinant in controlling the diagnostic performance of a thyrotropin assay in hyperthyroidism.

Humans↗

PubMed2003

Technical performance and diagnostic utility of the new Elecsys neuron-specific enolase enzyme immunoassay.

This international multicenter study was designed to evaluate the technical performance of the new double-monoclonal, single-step Elecsys neuron-specific enolase (NSE) enzyme immunoassay (EIA) and to assess its utility as a sensitive and specific test for the diagnosis of small-cell lung cancer (SCLC). Intra- and interassay coefficients of variation, determined in five control or serum specimens in six laboratories, ranged from 0.7 to 5.3 (inter-laboratory median: 1.3%) and from 1.3 to 8.5 (inter-laboratory median: 3.4%), respectively. Laboratory-to-laboratory comparability was excellent with respect to recovery and inter-assay coefficients of variation. The test was linear between 0.0 and 320 ng/ml (highest measured concentration). There was a significant correlation between NSE concentrations measured using the Elecsys NSE and the established Cobas Core NSE EIA II in all subjects (n = 723) and in patients with lung cancer (n = 333). However, NSE concentrations were systematically lower (approximately 9%) with the Elecsys NSE than with the comparison test. Based on a specificity of 95% in comparison with the group suffering from benign lung diseases (n = 183), the cut-off value for the discrimination between malignant and benign conditions was set at 21.6 ng/ml. NSE was raised in 73.4% of SCLC patients (n = 188) and was significantly higher (p < 0.01) in extensive (87.8%) as opposed to limited disease (56.7%). NSE was also elevated in 16.0% of the cases with non-small cell lung cancer (NSCLC, n = 374). It is concluded that the Elecsys NSE EIA is a reliable and accurate diagnostic procedure for the measurement of NSE in serum samples. The special merits of this new assay are the wide measuring range (according to manufacturer's declaration up to 370 ng/ml) and a short incubation time of 18 min.

Adenocarcinoma↗